The Directorate of Revenue Intelligence (DRI) has claimed to have unearthed customs duty evasion involving drug maker Zydus Cadila and water tank maker Sintex.

Last Friday, DRI officials seized the aircraft (Bombardier) worth Rs 70 crore that was being used by Zydus Cadila chairman and managing director Pankaj Patel and Sintex’s chairman Dinesh Patel.

According to officials, the aircraft was imported by a firm “Zysta Aviation” floated jointly by the two companies last year with 50% partnership each in it. The firm paid Customs duty under the category of Non-Scheduled Operators’ Permit (NSOP).

“NSOP is given to those who declare the aircraft to be used for commercial purposes. In this category, the customs duty is merely 5%. On the contrary, on the import of aircraft for personal use, the duty is as high has 17%. That is the fraud we have detected,” senior DRI officials said, requesting not to be named.

To evade duty, the company had declared the aircraft as to be used for charter services. However, DRI found in its investigation found that the aircraft was being used by the two companies. Officials said the investigation was still on but it had been established that the aviation firm itself is not into charter business.

Sources said the seized aircraft was parked at Sardar Vallabhbhai Patel International Airport and would be in DRI possession till the case is on.